ELECTROSTATICS

Electrostatic Precipitator By: Erin Chau 9A

What is an electrostatic precipitator?

An electrostatic precipitator is a filtration device that can easily remove fine matter like dust and smoke. This is very similar to the web scrubbers, but electrostatic precipitators only applies energy to the specific matter that is being collected. The first electrostatic precipitator was invented in 1907 by Dr. Frederick G. Cottrell. He created a device for charging particles and then collection them with electrostatic attraction. This is now better known as the electrostatic precipitator.

How It Works

An electrostatic precipitator has a row of very thin wires placed vertically with a group of large flat metal plates also placed vertically, with the plates usually spaced out around 1-18 centimetres apart. The air or gas flows across through the spaces between the wires, and then goes through the plates. A negative voltage made of thousands of volts is added in between the wire and plate. If the voltage that is applied is high enough, an electric discharge ionizes the gas around the electrodes. Negative ions will then go to the plates and eventually charge the gas particles.The ionized particles that now follow the negative electric field created by the power supply, moves to the grounded plates. Particles build up on the collection plates and create a new layer. This layer will not break because of the electrostatic pressure that is applied.
Electrostatic Precipitator System Working.avi

A simpler form

Are they still in use now?

Yes, electrostatic precipitators are used everywhere today. An example would be coal-fired boilers, and there are even precipitators that can remove droplets of water. Now, commonly thought of as air purifiers and furnace filters, electrostatic precipitators are everywhere. There are also simple solutions in cleaning these precipitators. Since the particles will eventually be very tight together, one can just simply drop it into a dish washer, or a solution supplied by the company.

Although useful, are they difficult to maintain?

With the constant need of clean plates, this invention is very sensitive. If a single plate is ruined, this may cause an effect on the entire machine. Any increase of dust, mis-wiring, increase or decrease of voltage can easily affect the precipitator. If there is an entire broken section, it is much easier to detect and fix rather than a small plate. With all these small details needed to take care of, electrostatic precipitators are very delicate inventions and need to be constantly checked.

Resources

Electrostatic precipitators. BBC. 2013. Web. February 2013. http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr_gateway/radiation/electrostaticsusesrev1.shtml


Electrostatic Precipitator. Neundorfer. Web. February 2013. http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx


Electrostatic Precipitator. Dictionary.com. Web. February 2013. http://dictionary.reference.com/browse/electrostatic+precipitator?s=t


Electrostatic Precipitator System Working. Youtube.com. Web. February 2013. http://www.youtube.com/watch?v=A0tDieiia_c"


Wet Type Electrostatic. Hitachi. Web. February 2013. http://www.hitachi-pt.com/products/energy/dustcollection/wet_type/index.html